Physicist Tom Krimigisdesigns scientific instruments for space; they’ve gone to every planet in the solar system. He’s the only person in the world with that achievement. Krimigis came to the United States from Greece at the start of the Space Age, and later led the Applied Physics Laboratory at Johns Hopkins University. He was recently in Flagstaff for an event at Lowell Observatory and spoke with KNAU’s Melissa Sevigny about his half-century tour of the solar system.

One of the first major studies of Pluto’s geology appears in the most recent edition of the Journal of Science. It used data from the New Horizons mission to get a better picture of the dwarf planet’s surface. As Arizona Public Radio’s Justin Regan reports, the study found that so-called “volatile materials” have shaped Pluto’s landscape.

Two California astronomers presented evidence for a new planet beyond Neptune on Wednesday. The prediction could reopen the debate about how a planet is defined, says an astronomer at Lowell Observatory in Flagstaff.